1. Field of the Invention
This invention relates to a ball throwing machine and more particularly to a ball throwing machine which forces the ball to be thrown through an off-center opening in a resilient disc.
2. Description of the Prior Art
Automatic pitching or ball throwing machines are utilized by many sporting organizations to provide practice and improve the skills of the players. To be effective the ball throwing machine must accurately simulate movement of a ball under actual playing conditions. For example, a right hand pitcher throws a ball which can curve to his left, while a left hand pitcher throws a ball which can curve to his right. Pitchers can also vary their velocity and provide other spins to cause the ball to move as desired. Likewise, balls which are hit, either on the ground or in the air, have various movement characteristics which the machine should accurately reproduce. An effective ball throwing machine must accurately and repeatably propel the ball with the desired movement.
Pneumatically operated ball throwing machines are old and well known in the prior art. For example, U.S. Pat. No. 1,379,403, issued May 27, 1921, discloses a pneumatic ball projector which utilizes compressed air for throwing the ball and also for causing the ball to follow a curved course the direction of which may be controlled by the operator of the machine. Grooves formed in the barrel of the machine determine the direction of curve of the thrown ball.
Other patents to pneumatic ball throwing machines such as U.S. Pat. No. 2,526,018, U.S. Pat. No. 3,584,614 and U.S. Pat. No. 2,935,980 disclose ball projecting machines which utilize friction strips or rails within a barrel to cause unequal drag on the thrown ball causing the ball to spin in a selected direction when ejected. As the ball is pneumatically forced down the barrel, movement of a portion of the ball is impeded so that the ball is spinning in a desired manner when it is projected from the machine.
While in other machines such as those shown in U.S. Pat. Nos. 3,467,073 and 3,662,729 pneumatically driven ball throwing machines have mechanical attachments for mechanically rotating the ball before it is pneumatically ejected from the throwing machine. For example, in U.S. Pat. No. 3,662,729 when a curve is desired, a motor is energized to spin the ball at a desired speed so that the thrown ball has this spin speed when ejected. In U.S. Pat. No. 3,467,073 rollers which can be rotated in an opposite direction spin the ball before the ball is launched from the pneumatic throwing machine.
Various toys have been disclosed for projecting light weight spheres usually in the form of a plastic table tennis ball. Typical of these toy type ball throwing devices are U.S. Pat. Nos. 2,505,428 and 2,975,779. A toy gun which projects ping-pong ball held by a resilient disc having a hole therein is disclosed in U.S. Pat. No. 2,505,428 issued Apr. 25, 1951. The toy gun disclosed in this patent is not concerned with throwing a curve ball. Also the toy gun could not project a relatively heavier ball with any substantial velocity. U.S. Pat. No. 2,975,779 issued Mar. 21, 1961, disclosed a toy curve ball projecting device utilizing a resilient ring with a centered hole formed therein through which the ball to be thrown is forced. The centered hole is adapted to cause different frictional engagement on various portions of the ball to be thrown; then a ball is forced through the resilient ring, it spins towards the created high friction side of the centered opening. The device disclosed in this patent is utilized for projecting light weight table tennis balls. There is no readily available means for preselecting the velocity of the balls to be projected. Also, no reservoir of compressed air is provided and the device is not operable for throwing heavier balls, such as tennis or baseballs, at high speeds for a relatively long distance.
It is desirable to have a ball throwing device which can be easily aimed and is adjustable for speed and direction of curve. It is also advantageous for the throwing machine to be relatively light weight and portable for use in various areas. The machine should also be easily adjustable to allow for different uses.